December 2025 Performance Summary: Focused on multithreading and memory management optimization in the Redot Engine core and GDScript VM, with alignment to the 4.5 release goals. Replaced spin locks with mutexes to improve thread safety and scalability, and introduced block-based object storage to optimize memory usage and access speed. This work enhances runtime stability, reduces contention, and improves cache locality, laying the groundwork for improved performance in complex scenes and scripting workloads. No separate bug-fix entry was tracked this month; the primary value came from architectural improvements and a cleaner concurrency model.